Speaking before last night’s premiere of his new film What We Did On Our Holiday, the father of five says: “They cut out the prostate through that miniature stuff, just two wee holes. I don’t know if there’s a risk of the cancer spreading, not that they told me. I don’t ask.

“I am very much on the outside of it all. I don’t really bother much about it.

“The blood clot was in my right leg and it was part of the cancer. I went for a walk and got in terrible pain and I had to come home. My leg was all swollen and Pamela drove me to the hospital.

“According to Pam it was touch and go but I am an outsider to these things.

“I am a bit of a dimwit, I flit around on the outside of it all.”

Billy Conolly and his wife Pamela Stephenson

Free of cancer and gallstones, Billy is coping with the Parkinson’s. His hands are firm and steady as he drinks a glass of water at London’s Soho Hotel.

He says: “I have Parkinson’s disease, it’s OK. I am seeing a specialist and he took me off the drugs I was on. I was on stuff called ReQuip but the side-effects were stronger than the effects. It brought on a kind of dullness.”

Glasgow-born Billy stumbled into stardom. His mother abandoned him when he was four and his father sexually abused him.

Young Billy trained as a boilermaker in the shipyards but in his spare time he was a folk singer, finding fame with the late Gerry Rafferty in The Humblebums.

His switch to comedy was a success and from stand-up, and his acclaimed appearances on Michael Parkinson’s chat show, he branched out into film.

He says: “Some people go on the internet and research it and they email me and say ‘I have discovered this about Parkinson’s.’ I’m ‘f*** off, talk about something else’.

“Others say ‘We are meeting on Wednesday’. I can’t think of anything worse than sitting looking at the worst guy in the room and thinking ‘that’s how I’m going to be’. F*** that!”

He did make an exception for one man – old pal Robin Williams. Like Billy, the Good Morning Vietnam star was diagnosed with Parkinson’s but told only close family and friends.

He turned to the comedian, who had gone public about his condition the year before, for guidance.

Billy said: “He was diagnosed after me and was on the phone a lot asking me about it. But phoning me for advice is an absolute waste of f***ing time because I don’t have it.

“It broke my heart when he died. I was in Malta with my family and my children were all crying. They all loved him. He is a stunning guy. You notice I don’t speak about him in the past tense? It’s still not sunk in, I keep expecting him to walk in.”

The pair first met on a Canadian talk show 30 years ago and Billy recognised a rare talent.

They became firm friends and Robin was a regular summer guest at his former Scots home Candacraig.

Just days before he took his life, Robin called to thank him for the tip. Billy said: “He phoned me and said, ‘It’s brilliant, it’s working’.

“He kept telling me he loved me. I said ‘I know’. But he kept repeating it. I was thinking what the f*** is he on about?

“After his death I thought ‘Oh my God he was saying goodbye’.”

Reuters

Billy Connolly puts his arm around Robin Williams at the finish of the hill race at Lornach Highland gathering in Strathdon in 2000

Like all of Robin’s fans, Billy wants to remember the happiness his friend left behind. He said: “I know nothing about it but it seems to me that everything got on top of him, his show coming off the TV, his age, Parkinson’s and blah blah blah. And he just did the thing.

“But his legacy is immense. His record is there for everybody to see. He was such a joy, he never had a bad word to say about anybody.

“I enjoy bitching about people. He would just laugh.”

Last June, at the height of the midge season, Billy headed to the Highlands to film bittersweet comedy What We Did On Our Holiday, made by the team behind TV comedy Outnumbered.

Starring with Rosamund Pike and David Tennant, he plays a grandfather with terminal cancer who has his family descend on him for an unwanted birthday party.

All through filming he kept his own cancer secret from the cast and crew.

Billy said: “My character is a lovely guy who just wants to be on his own. He is kind of sick, not unlike myself, and he’s a bit grumpy.

“At the time I knew I had cancer but I had not been operated on.

“I hadn’t told them and in the movie I have to say to my granddaughter ‘I have cancer’ and it was the first time I had said those words to anybody apart from Pamela and the family. But no one else.

“It was very peculiar and strangely eerie, that moment.

“It was quite easy to get into the mood of the character because it was very real to me.”

As I leave him to prepare for the premiere, Billy shakes my hand.

Despite everything he’s been through, he still has the grip of a Glasgow boilermaker.